Expression Characteristics And Functions Of Bxy4022 Gene In Pine Wood Nematode,Bursaphelenchus Xylophilus

Bursaphelenchus xylophilus is the most serious pathogenic nematodes in forestry and have brought devastating disasters to pine forests in worldwide.When a healthy pine tree is infected with pine wood nematodes,it could die within two months.In such case,the high-efficient copulating and rapid reproduction are the most important causes leading to the epidemic of this disease.Bxy4022 gene encodes a G protein-coupled receptor and is expressed dynamicly in B.xylophilus at different different development stages.As a member of the neuropeptide receptor family,Bxy4022 gene plays different roles at different development stages,and also between male and female of B.xylophilus,especially in the mating process.In the present paper,we carried out the in-situ hybridization test in B.xylophilus and trans-genenic microinjection using Caenorhabditis elegans as an agent to study the spatio-temporal dynamic expression characteristics of Bxy4022.RNAi test was also carried out to clarify the biological functions of Bxy4022 gene.The results are as follows:1.The results of bioinformatic analysis showed that the protein expressed by the Bxy4022 in B.xylophilus was a G protein-coupled receptor,and the npr-21 gene of C.elegans had the highest similarity to Bxy4022.2.The results of in situ hybridization and trans-genenic microinjection showed that Bxy4022 was expressed dynamically throughout the development of B.xylophilus.In the embryonic and larval stages,Bxy4022 is expressed extensitvely in the nerve system of head,intestine,ventral nerve cord,tail nerve and excretory hole.In adulthood,Bxy4022 is mainly expressed in female pubic muscles and male tail neurons.3.RNAi results showed that Bxy4022 gene was mainly involved in the regulation of muscular nervous system,pharynx and digestive system of B.xylophilus in larval stages,affecting the movement,feeding and development of juveniles.In the adult stage,Bxy4022 is mainly involved in regulating the transmission of nerve signals in muscles and signals related to the sexual organs of B.xylophilus.Nematode can not control its activity,and failed to mate after being interfered by RNA of Bxy4022.Our results demonstrated the important roles of the Bxy4022 in the development and signal transmission,leading to the lose of ability in movement,feeding,mating and reproduction of B.xylophilus,which provide promising hints for control against pine wilt disease by blocking ontogenesis,decreasing nematode fecundity,and disrupting the connection between B.xylophilus and its vector beetle by preventing nematode movement into the tracheal system.